Nowadays as an alternative to usual, hinged doors, solutions are known for sliding doors that can be applied both to wardrobes and pieces of furniture in general, and also to door and window frames or to any other application of closing elements that require a reduced space when open.
Usually such types of door are constituted by one or more door leaves, each one of which has brackets with rolling means that are guided by a rail, which is constituted by an upper guide and by a lower guide, which respectively are applied to the ceiling and optionally to the floor of the compartment to be closed.
It is known to fit the door leaf with a device to return it to the open position, which can be disengaged as needed when it is desired to close the sliding door, or to the closed position, when it is desired that the door leaf follow a guided closure.
A problem that is found in conventional sliding door leaves is constituted by the fact that the door leaf can remain partially closed or partially open or it can slam, on the jambs of the door or on the sides of the item of furniture, when the door leaf is completely opened or completely closed.
A partial solution to such drawback is known from EP1658785 which discloses to a device that is adapted to assist and guide the movement of a door leaf, which comprises a receptacle inside which is placed a damper, a spring, and an entrainment element that can be accommodated within a pair of teeth that are associated with a coupling element which comprises a guiding pin that can slide into an upturned L-shaped guide.
The device is arranged proximate to one end of the compartment.
For example, when opening the door leaf, at a certain point the device hooks the entrainment element that activates the damper until the pin is positioned, through the L-shaped guide, in a stable and stationary condition: when the door leaf is closed, the entrainment element interacts with the pair of teeth and activates the damper which thus gently accompanies the door up until the condition where it is completely closed.
Such solution however suffers some drawbacks: the device is in fact complex in terms of construction in that it is constituted by a plurality of elements that have to be put together in advance while paying great attention to the elements of play that exist for example between the L-shaped guide and the pin that rests in it, since any sticking or the creation of friction could defeat the operation of the device and thus prevent the correct closing or complete opening of the door leaf.
Furthermore, conventional return devices suffer other criticalities which are linked to the fact that the return spring does not have a constant force along its stroke.
This causes problems with the return along the final part of the stroke because the force is low and there are, inversely, problems with opening the door in the final part when the door is released, where the force of the spring is too high.
This, combined with the fact that the connection to the return mechanism of the door in motion occurs by way of mechanical means, creates bothersome noise in operation.
EP 2455571 is also known, and discloses a mechanism for forcible movement which comprises a first urging body to apply a force toward a certain position for a fixed body in a standby position.
A striker body is captured at a prescribed position by the fixed body which is held in standby position, and a movable body is moved up to a position at end of movement by way of the relative movement of the fixed body to the determined position by the release of the hold on the occasion of the capture.
A damping mechanism comprises a contact part for connection with the fixed body constituting the mechanism for forcible movement, a second body urging the contact part in an advancement direction.
The damping mechanism is constituted so as to apply a resistance to a retraction of the contact part accompanying the movement of the fixed body to the determined position.
Such solution also suffers the same drawbacks mentioned previously.
EP 2557259 is also known, which discloses a braking device that comprises pneumatic braking means which can be activated by way of a slider interacting with a fixed frame, for example of the door; in one embodiment there is a piston the rod of which is provided, at the end tip, with a magnetic head the function of which is, once it has come into contact with a fixed L-shaped profile with one wing positioned head-on to the magnetic head, to allow the rod to be extracted from the stem of the piston.
Such solution suffers many drawbacks such as the considerable length required for the braking device, the stem of which is subject to possible breakage or sticking; furthermore, the reliability of the pneumatic functionality is poor.
Finally the sole function of the magnetic head is to directly couple to a fixed body, arranged along the same axis, for the extraction of the stem.
EP 2330269 is also known, which discloses a sliding guide for doors of wardrobes which has a damper stop comprising a trolley consisting of a first frame and a second frame shaped like an upturned “U” to which the upper ends of an outer or inner door are fixed.
The damper stop comprises an air or gas damper fixed outside two seats which are provided on a section associated with the trolley.
Such solution also suffers many drawbacks, such as the use of a gas damper which, moreover, is arranged laterally to the trolley so as to increase the space taken up and render the guide barely usable.